Corded-spring energy control device

ABSTRACT

A device for automatically controlling the elastic energy of a coiled spring when an operation lever pivotally supported by a shaft and normally urged in one direction by one end of the coiled spring is caused to move in the other direction against the biasing force of the spring. The device comprises means to relieve the other end of the coiled spring when the operation lever is moved in the other direction as aforementioned so as to thereby restrict an increase in the elastic energy of the coiled spring.

United States Patent Hirafuji 1 Mar. 7, 1972 [54] CORDED-SPRING ENERGYCONTROL DEVICE [72] Inventor: Ban Hirafuji, Yokohama, Japan [73]Assignee: Ricoh Co., Ltd., Tokyo, Japan [22] Filed: Apr. 23, 1970 [21]Appl. No.: 31,328

[301 Foreign Application Priority Date May 31, 1969 Japan ..44/42788[52] US. CL ..74/519, 74/104, 74/470,

74/491 [51] Int. Cl. 605g 1/04 [58] Field of Search ..74/470, 491, 104,519

[56] References Cited UNITED STATES PATENTS 1,816,164 7/1931 Wood..74/519 X Primary Examiner-Milton Kaufman Attorney-Henry T. Burke,Robert Scobey, Robert S. Dunham, P. E. Henninger, Lester W. Clark,Gerald W. Gn'ffin, Thomas F. Moran, R. Bradlee Boa! and Christopher C.Dunham [5 ABSTRACT A device for automatically controlling the elasticenergy of a coiled spring when an operation lever pivotally supported bya shaft and normally urged in one direction by one end of the coiledspring is caused to move in the other direction against the biasingforce of the spring. The device comprises means to relieve the other endof the coiled spring when the operation lever is moved in the otherdirection as aforementioned so as to thereby restrict an increase in theelastic energy of the coiled spring.

4Claims,4l)rawingFigures PATENTEIJHAR 7 I972 3 646 8 3 2 INVENTOR BAN///A,4 FZ/J/ ATTORNEY CORDED-SPRING ENERGY CONTROL DEVICE BACKGROUND OFTHE INVENTION In one linkage known in the art, an operation leverconnected at its free end to one end of a sliding member adapted to movelinearly in reciprocating motion is pivotally supported at its base by ashaft and normally urged in one direction by a coiled spring. In causingthe sliding member to move linearly in reciprocating motion, an externalforce is exerted on the sliding member and hence the operation lever tocause them to move in a direction opposite to the direction in which theoperation lever is normally urged. The operation lever moves in pivotalmotion about the shaft against the biasing force of the spring. When thesliding member reaches a predetermined point, the external force isremoved to permit the sliding member and the operation lever to returnto their starting positions by virtue of the biasing force of thespring. Then, an external force is exerted again and this cycle ofoperation is repeated so that the sliding member may move in linearsliding motion. Such linkage is in practical use, for example, with thepin box of a portable calculating machine.

When the forces moving the sliding member in linear reciprocatingmotion, particularly the force which causes the operation lever to movein pivotal motion against the biasing force of the spring, are appliedto the sliding member and operation lever of the conventional linkagedescribed, the resilience of the coiled spring shows a variation inmagnitude depending on the degree of displacement of the operationlever. Therefore, when the free end of the operation lever is movedagainst the biasing force of the coiled spring, the force exerted on theoperation lever must be greater in the terminating stage of the pivotalmovement of the lever than in the initial stage thereof in order thatthe reciprocating movement of the sliding member may take placesmoothly.

The mechanism of the type mentioned above in which a sliding member ismoved by an external force in a direction opposite to the direction inwhich a member connected to the sliding member is normally urged by acoiled spring, tension spring or compression spring can have applicationin not only the pin box of a portable calculating machine but also inother equipment. In such applications, it is desirable that the forcewhich moves the sliding member in linear reciprocating motion bemaintained constant.

If the coiled spring had a length which is sufficiently great to renderthe displacement of the operation lever insignificant, the elasticenergy of the spring could be maintained constant regardless of theextent of displacement of the operation lever. However, this arrangementis not possible because an increase in the length of the spring makes itimpossible to obtain a compact overall size in a portable calculatingmachine.

SUMMARY OF THE INVENTION This invention relates to devices forcontrolling the elastic energy of a coiled spring. More particularly,the invention is concerned with a device for automatically controllingthe elastic energy of a coiled spring when an operation lever normallyurged in one direction by the coiled spring is caused to move in theopposite direction against the biasing force of the spring.

An object of the invention is to provide a device for automaticallycontrolling the elastic energy of a coiled spring which permits theresilience of the coiled spring to remain substantially constant when anoperation lever under the influence of the coiled spring is caused tomove in pivotal motion.

Another object of the invention is to provide connecting means effectiveto connect the operation lever under the influence of the coiled springwith a pivotal member.

Additional objects as well as features and advantages of this inventionwill become evident from the description set forth hereinafter whenconsidered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. 1 is a plan view of one embodiment of the device for automaticallycontrolling the elastic energy of a coiled spring according to thisinvention;

FIG. 2 is a partial plan view of the device according to this inventionas it is used as means for moving the pin box of a portable calculatingmachine;

FIG. 3 is a plan view of another embodiment of the device according tothis invention; and

FIG. 4 is a perspective view of the device shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, an operation lever lpivotally supported by a shaft 2 connected to a fixed member (not shown)is formed integral with a segmental gear lb at its base portion la. Thesegmental gear lb is in meshing engagement with a segmental gear 4aformed at one end of a pivotal member 4 which is pivotally supported atthe other end by a fixed shaft 3.

The operation lever l is normally urged in the direction of arrow a inFIG. 1 by a coiled torsion spring 5 which comprises a main body 50loosely mounted on the shaft 2, one end portion 5b maintained inengagement with an eccentric cam 6 adjustably mounted on the operationlever l, and the other end portion 50 maintained in engagement with aroller 7 mounted on a pin fixed to the pivotal member 4. The movement ofthe operation lever 1 by the biasing force of the coiled spring 5 isrestricted by a fixed pin 8 which engages one side of the operationlever 1.

If the operation lever l is moved by an external force in pivotal motionin a direction opposite to the direction of arrow a in FIG. 1 againstthe biasing force of the coiled spring 5, the lever 1 will move from asolid line position to a broken line position 1A. The pivotal member 4having the segmental gear 411 in meshing engagement with the segmentalgear lb of the lever 1 will also move in pivotal motion from a solidline position to a broken line position 4A. Likewise, the eccentric cam6 and roller 7 will move from solid line positions to broken linepositions 6A and 7A respectively, so that opposite ends of the coiledspring 5 will move from solid line positions to broken line positions.

The torsional moment Tof the spring 5 can be given by the formula whereK is the spring constant and 9 is the angle formed by the two endportions 5b and 5c of the spring 5. In the embodiment described above,the difference between the angle 0 of the spring 5 before thedisplacement of the operation lever takes place and the angle 0 of thespring 5 after the displacement of the operation lever has taken placeis small in spite of the substantial angle of pivotal movement of theoperation lever, so that no great variation is caused in the elasticenergy of the coiled spring 5. If the value of 0 is maintained constantat all times, the resilience of the coiled spring 5 will remain constantat all times during the pivotal movement of the operation lever 1. Bygradually increasing or reducing the value of 0, the resilience of thecoiled spring 5 can be varied as desired.

The embodiment described above is an example in which the angle isgradually reduced. That is, the angle 6 after the displacement of theoperation lever is smaller than the angle 0, before the displacement.However, the difference between the two angles 0 and 0, is much smallerin this embodiment than in prior art arrangements in spite of thesubstantial angle of pivotal movement of the operation lever 1. Althoughthe elastic energy of the spring 5 gradually increases as thedisplacement of the operation lever 1 increases, no significant increaseis caused in the resilience of the spring 5 as aforementioned.

The eccentric cam 6 permits the resilience of the coiled spring 5 to bevaried as desired after the parts are assembled. Any other suitablestopper means may be substituted for it.

FIG. 2 shows an example of a linear movement device wherein the linkageof the embodiment just described is utilized for maintaining constantthe resilient restoring force imparted to a sliding member 21 as much aspossible. In FIG. 2, the sliding member 21 slidably supported by a fixedshaft 28 is adapted to move in the direction of arrow b in intermittentmovement by virtue of a rack 21b. Such sliding member 21 is used as acarrier of the pin box of a portable calculating.

machine wherein it is required to impart a substantially constantresilient restoring force to the sliding member during its movement. Thesliding member 21 has a bent portion 21a at its left end as seen in thefigure which is loosely held by a pair of fingers 23a and 23b formed atthe free end of an operation lever 23 pivotally supported by a shaft 22secured to a fixed member (not shown) of the calculating machine. Acoiled spring 24 mounted on the shaft 22 engages a pin 25 on theoperation lever 23 and a pin 26 (corresponding to the roller 7 inFIG. 1) on a pivotal member (not shown) which moves as the pin 25 moves.

The operation lever 23 is normally urged in the direction of arrow bythe spring 24, its movement in the indicated direction being restrictedby a fixed pin 27. If the sliding member 21 is moved in the direction ofarrow b and the bent portion 21a moves to a broken line position 2laA,the operation lever 23 will move against the biasing force of the spring24 to a broken line position 23A, with the pins 25 and 26 moving tobroken line positions 25A and 26A respectively. As a result, the spring24 moves to a broken line position 24A. In this state, a resilientrestoring force acting in a direction opposite to the direction of arrowb is imparted by the spring 24 to the sliding member 21 through theoperation lever 23.

The resilience of the spring 24 to which the sliding member 21 issubjected is maximized when the bent portion 21a of the sliding member21 and operation lever are aligned vertically, since the sliding member21 moves in linear motion and the operation lever moves in rotationalmotion. The resilience is gradually reduced after the sliding member 21has passed a position in which the bent portion 21a is alignedvertically with the operation lever 23. On the other hand, the amount ofdisplacement of the pin 26 relative to the amount of displacement of thepin 25 is set such that the resilience of the spring 24 acting on theoperation lever 23 is gradually increased as the displacement of thespring increases. Thus, the resilience of the spring 24 acting on thesliding member can be maintained substantially constant regardless ofthe position in which the sliding member 21 is disposed.

FIGS. 3 and 4 show another embodiment of the device for automaticallycontrolling the elastic energy of a coiled spring according to thisinvention. An operation lever 41 pivotally supported by a fixed shaft 42is formed integral with a segmental gear 41b in its base portion 410.Mounted on the shaft 42 is a main body 430 of a coiled spring 43 whichhas one end 43b engaging a pin 44 secured to the operation lever and theother end 430 engaging a pivotal member 45 pivotally supported by theshaft 42. The pivotal member 45 is formed integral with a segmental gear450. The segmental gears 45a and 41b are in meshing engagement withsegmental gears 47a and 47b respectively formed in a gear member 47pivotally supported by a shaft 46.

The operation lever 41 is normally urged in the direction of arrow d inFIG. 3 by the spring 43, and its movement in the indicated order isrestricted by a fixed pin 48. The ratio of the radius of rotation of thesegmental gear 41b to the radius of rotation of the segmental gear 47bhas a value which differs from the value of the ratio of the radius ofrotation of the segmental gear 47a to the radius of rotation of thesegmental gear 450. Thus, it is possible to linearly increase or reducethe resilience of the spring 43 acting on the operation lever as thelatter moves in pivotal motion. If the values of the two ratiosmentioned above are so set that there is no substantial differencebetween them, the resilience of the spring 43 will undergo substantiallyno change even if the operation lever 41 moves in pivotal motion.

In the two embodiments described above, gear means 15 used as means formoving the pivotal member in response to the movement of the operationlever. It is to be understood that any other suitable meanssuch asforked levers engaging each other may be used.

What I claim is:

1. A device for controlling the elastic energy of a coiled spring,comprising an operation lever pivotally supported on a shaft, a memberpivotally supported for motion about an axis extending in the samedirection as said shaft, a coiled spring having one end engaging saidoperation lever and the other end engaging said member, connecting meansfor connecting said operation lever with said member and moving thelatter in conjunction with the former as the former is moved in pivotalmotion so as to thereby restrict an increase in the elastic energy ofsaid spring, and stop means for restricting the pivotal movement of saidoperation lever caused by said spring.

2. A device for controlling the elastic energy of a coiled spring as inclaim 1, wherein said connecting means comprises a first segmental gearfixed to said operation lever for concurrent movement therewith, and asecond segmental gear fixed to said member for concurrent movementtherewith, said two segmental gears being maintained in meshingengagement with each other, and said operation lever and said memberbeing supported on parallel shafts.

3. A device for controlling the elastic energy of a coiled spring as inclaim 1, wherein said connecting means comprises two segmental gearsrespectively fixed to said operation lever and said member forconcurrent movement therewith, said lever and said member beingpivotally supported by the same shaft, and two segmental gears fixed toeach other for concurrent movement and supported by a second shaftparallel to said shaft supporting said operation lever and said member,said last-mentioned two segmental gears having different radii ofrotation, the segmental gear of larger radius of rotation being inmeshing engagement with the segmental gear formed integral with saidoperation lever and the segmental gear of smaller radius of rotationbeing in meshing engagement with the segmental gear formed integral withsaid member.

4. A device for controlling the elastic energy of a coiled spring as inclaim 1, wherein said operation lever is connected at its free end to asliding member for supporting a pin box of a portable calculatingmachine.

1. A device for controlling the elastic energy of a coiled spring,comprising an operation lever pivotally supported on a shaft, a memberpivotally supported for motion about an axis extending in the samedirection as said shaft, a coiled spring having one end engaging saidoperation lever and the other end engaging said member, connecting meansfor connecting said operation lever with said member and moving thelatter in conjunction with the former as the former is moved in pivotalmotion so as to thereby restrict an increase in the elastic energy ofsaid spring, and stop means for restricting the pivotal movement of saidoperation lever caused by said spring.
 2. A device for controlling theelastic energy of a coiled spring as in claim 1, wherein said connectingmeans comprises a first segmental gear fixed to said operation lever forconcurrent movement therewith, and a second segmental gear fixed to saidmember for concurrent movement therewith, said two segmental gears beingmaintained in meshing engagement with each other, and said operationlever and said member being supported on parallel shafts.
 3. A devicefor controlling the elastic energy of a coiled spring as in claim 1,wherein said connecting means comprises two segmental gears respectivelyfixed to said operation lever and said member for concurrent movementtherewith, said lever and said member being pivotally supported by thesame shaft, and two segmental gears fixed to each other for concurrentmovement and supported by a second shaft parallel to said shaftsupporting said operation lever and said member, said last-mentioned twosegmental gears having different radii of rotation, the segmental gearof larger radius of rotation being in meshing engagement with thesegmental gear formed integral with said operation lever and thesegmental gear of smaller radius of rotation being in meshing engagementwith the segmental gear formed integral with said member.
 4. A devicefor controlling the elastic energy of a coiled spring as in claim 1,wherein said operation lever is connected at its free end to a slIdingmember for supporting a pin box of a portable calculating machine.